PI has a long track record of working with OEMs in the most demanding industries from Semiconductor Technology to Medical Design – industries where product performance, quality, and the ability to ramp up quickly are not the only parameters required to satisfy the customer's demands. Working with technology leaders all around the world forces you to continuously improve your yield, process, and product performance. And unless your quality is outstanding, you cannot become a key supplier to major US, European, and Japanese companies in the Optics, Photonics, Semiconductor, and Automotive industry.

PI is a supplier of high-end precision motion systems and makes use of own drive components and high-precision positioners to build customized positioning and automation sub-systems —“motion engines”—for our customers. With the largest portfolio of precision motion technologies in the industry, PI engineers have the best foundation to find a solution that matches your requirements in terms of precision, quality and budget – in a timeframe that works for you.

Select the product type specified by the axes of motion required. Selection of more criteria expands or shortens the list of results. Select more than one filter at at time, for example, to find positioning stages designed for higher load capacity, too.

Air bearings provide advantages over mechanical bearings when vibration-free motion is required, highly constant velocity control is crucial, and when angular repeatability and geometric performance must be optimal. Air bearing stages (linear, rotary, and spherical) replace mechanical contact by a thin air film, avoiding wear, friction, vibration, and hysteresis effects.

PI offers the broadest and deepest range of precision motion technologies for micro and nano precision applications. Our engineers work with our customers to find the best drive and bearing technology for each individual application. Having access to multiple drive and positioning technologies allows an open discussion with a better outcome for the customer.

The PI group employs over 1,200 people in 15 countries and runs engineering and manufacturing centers on 3 continents. Select from the broadest portfolio of precision motion technologies, including piezoelectric and air bearing systems, with 1,000’s of standard products or have our engineers provide you with a custom solution.

A gantry precision positioning stage is sometimes called a linear robot or Cartesian robot. Gantries typically provide motion in 2 or 3 linear degrees of freedom (X-Y and X-Y-Z) and are often used for pick and place applications, 3D printing or laser machining, and welding applications.

Hexapod positioners are often referred to as Stewart Platforms. A hexapod is based on a 6-axis (XYZ, Pitch, Roll, Yaw) actuator system arranged in parallel between a top and bottom platform. PI parallel kinematics (PKM) precision positioning systems have many advantages over serial kinematics stages, such as lower inertia, improved dynamics, smaller package size and higher stiffness. In addition hexapods are more flexible than conventional 6 axis positioners.

There are several ways to achieve nanometer precision motion. The best positioning systems avoid friction all together, in both the drive system (motor) and in the guiding system (bearings). Frictionless bearings also avoid the bearing rumble caused by balls and rollers and provide vibration-free motion with highly constant velocity.

Piezo Motors are intrinsically vacuum compatible, non-magnetic and self locking at rest, providing long travel compared to traditional piezo mechanisms. The individual drive concepts are optimized for different applications, they differ in their design, size, cost, force & speed and other performance parameters.

Why All Piezo Motors are NOT Created Equal: The piezoelectric effect for precision motion control - PI Physik Instrumente.

The demand for higher speed and/or precision in fields such as bio-nanotechnology, semiconductors, metrology, data comm, and photonics keep pushing manufacturers to come up with innovative drive technologies.

Piezoelectric translators (transducers) are precision ceramic actuators which convert electrical energy directly into linear motion with high speed, force and virtually unlimited resolution. These actuators are used in every modern high tech field from semiconductor test & inspection to super-resolution microscopy, bio-nanotechnology and astronomy/aerospace technology.

Developing and manufacturing piezo ceramic materials and components are complex processes. PI Ceramic - PI’s piezo material design and manufacturing facility - boasts several decades of experience as well as the right tools for rapid prototyping of custom engineered piezo components and assemblies. From the formulation of advanced piezo materials to the processing steps such as cutting, milling, grinding, and the precision assembly, every stage is controlled by our engineers and product specialists.

A piezo controller or driver is used to control the motion of a piezo positioning device. There are open and closed loop controllers. Open-loop controllers are often referred to as piezo driver or even piezo power supply. Closed-loop controllers are divided in two basic types: analog-servo and digital servo controllers.

PI provides a large variety of hardware & software solutions for high precision motion control. Our portfolio spans from integrated compact single axis servo controllers / drivers, such as popular Mercury-class motion controllers, to complex multi-axis systems for parallel-kinematics positioners, such as hexapods.

Standardization is common with adapter plates and brackets, but we can create a custom accessory to fit your application system. PI products ship with the required cables. Customization is always an option.

PI’s tech blog offers over 40 years of insight into innovative applications of precision motion control, nanopositioning, and micropositioning in industry, science, and research. We hope the PI blog is an enjoyable and informative resource, and a starting-point for innovation across disciplines.

PI’s tech blog offers over 40 years of insight into innovative applications of precision motion control, nanopositioning, and micropositioning in industry, science, and research. We hope the PI blog is an enjoyable and informative resource, and a starting-point for innovation across disciplines.

PI’s tech blog offers over 40 years of insight into innovative applications of precision motion control, nanopositioning, and micropositioning in industry, science, and research. We hope the PI blog is an enjoyable and informative resource, and a starting-point for innovation across disciplines.

PI products are often used at the cutting edge of technology. They solve critical motion problems in lithography, microscopy, astronomy, laser technology, photonics and semiconductor manufacturing on locations around the world and in places as remote as the Science Lab on the Mars Rover.

PI positioning systems are employed where technology is pushed forward in industry and research. This is done, for example, in semiconductor manufacturing, in medical engineering, in biotechnology, in plant engineering, in surface metrology, or in astronomy.

Because the need for multi-axis and also precision robots in production and quality processes is on the increase, industry is looking out for new types of robotics. PI offers parallel-kinematic hexapods for these tasks.

Lithographic processes are the reason why chips are getting smaller and smaller and why extremely fine structures can be realized on silicon wafers. Piezo drives have made these technical advances possible with their performance and reliability.

Progress in pharmaceutical research, diagnostics, and therapy requires high-performance and precise position systems. In addition to high positioning precision, requirements for the drives often include compact dimensions, low energy consumption, speed, and high reliability.

Efficiency has become an important buzzword these days. Materials research has paid a major contribution as the results have, for example, optimized processing methods. Methods such as X-rays and lasers or white light interferometry demand precise positioning of the specimens to be examined and of optics or beam control.

The assembly of complex optical systems like objective lenses for smartphone cameras or laser cavities requires more and more accuracy. Active alignment addresses the resulting needs and helps to reduce cycle times by two orders of magnitude and more.

PI combines its long-term experience in micro and nanopositioning technology with in-depth knowledge in the fields of mechanics, electronics, sensor engineering, and software. Thus, PI is able to offer its customers the most advanced drive technologies and system solutions.

PI Ceramic offers a wealth of experience in the manufacturing of piezoceramic materials, components, and actuators. The piezoceramic materials can be adapted individually to perfectly fit the later use of the piezo components.

Depending on the configuration and control, piezoceramic actuators can be used to create translational motions or as motors with a virtually unlimited travel range. The choice of drive depends on the requirements of the application.

Rotating electric motors such as DC or stepper motors are used in connection with screw or worm drives. Stepper motor systems with high-resolution encoders can perform minimum incremental motions of 10 nm with high reliability and repeatability.

In a parallel-kinematic, multi-axis system, all actuators act directly on a single moving platform. This means that all axes can be designed with identical dynamic properties, thus reducing the moved mass considerably. Hexapods are used for moving and precision positioning, aligning and displacing loads in all six degrees of freedom, i.e., three linear and three rotational axes.

The linearity and repeatability achieved are not possible without highest-resolution measuring devices. Accuracies in the range of a few nanometers and below require a position measurement method that can also detect motion in this range.

Fast settling or extremely smooth low speed motion, high positional stability, high resolution and high dynamics – the requirements placed on piezo systems vary greatly and need drivers and controllers with a high degree of flexibility.

Careful handling, adequate premises: PI does not only have the necessary equipment for the qualification of materials, components and final products, but also has many years of experience with regard to HV und UHV positioning systems.

Talk to our engineers first. They have access to in-depth knowledge and test data on diverse driving and guiding technologies, spanning from electromagnetic to piezoceramic and from mag-lev to air bearings. They also have experience selecting the right technology for each individual application. Often an adaptation of existing technologies/products will suffice to solve a problem. However, experience along with detailed knowledge and PI’s significant R&D investment in new technologies enables our engineers to take unique approaches.

PI offers sound training in technical and business careers with a future. Pupils, students, graduates and professionals can get involved at PI and will be supported by us in their professional and personal further development.

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while preventing plenty of headaches in the future.

Talk to our engineers first. They have access to in-depth knowledge and test data on diverse driving and guiding technologies, spanning from electromagnetic to piezoceramic and from mag-lev to air bearings. They also have experience selecting the right technology for each individual application. Often an adaptation of existing technologies/products will suffice to solve a problem. However, experience along with detailed knowledge and PI’s significant R&D investment in new technologies enables our engineers to take unique approaches.

What is the Difference between Parallel Positioners and Stacked Serial Kinematics?

When faced with a multi-axis motion application, many users stack motion stages, and in fact that is a fine approach for assemblies of just a few axes. But as applications become more complex, so do the equivalent stacks-of-stages, and very real and practical considerations begin to come into play.

Stiffness. Some stage manufacturers publish stiffness specifications in terms of axial deviation per unit force, but this is of little utility in estimating the dynamic performance of a stage …or a stack. A more pertinent metric is the resonant frequency, as it integrates both the effective coefficient of stiffness of a mechanism and the summed mass of its construction. (Accordingly, knowing Fres means you can easily estimate the possible step/settle time for a well-tuned closed-loop stage: approximately [3 Fres]-1). In our experience, most high-quality conventional linear stages will exhibit resonant frequencies on the order of 75-120Hz, unloaded. Stack them, and the resulting structure can have significantly limited responsiveness and long settling times.

Hexapods with cardanic Z-offset joints combine high stiffness with high precision as shown in the graphs above. Here, Y-axis motion of an H-811 hexapod is measured with a laser interferometer, to determine linearity and repeatability. For full travel moves, the RMS repeatability is ±71nm and ±55nm for 2mm travel. The X and Z performance is on the same level. (Image: PI)
Learn more

Inconsistent dynamics. The bottom stage in a stack carries the mass of the entire stack, and so on up to the top stage, which carries only the application load. So tuning is a laborious, axis-by-axis process, with different settings for each axis… and consequently different responsiveness.

Inflexible rotation-centerpoint placement. Stacked stages place the center of their tip/tilt and rotation motions at the geometric centers of each rotation-stage and goniometer bearing. These can sometimes be arranged to coincide at a desired point in space (for example, at the focal point of a lens) via custom adaptor plates and fixtures, but this takes time and effort and is inflexible should application needs change. And significant changes can alter the dynamics of the stack, necessitating a re-tuning of each axis… again.

Cabling. Cables are a fact of life in motion control, and managing them deserves more attention than it often gets. To begin, cables can be a conduit for vibration that can impact an entire application setup in un-obvious ways. Even one’s choice of draping the cables off an isolation platform can influence an application’s overall stability and performance in profound ways. As a stage moves, any cable being dragged along can contribute to parasitic motions and other errors. Stiff cables can do so even if arranged in a non-dragging manner. Cables can break and snag and come loose, contributing to premature failures that can be hard to diagnose. And generally, these problems scale with the number of axes in a user-stacked system. (Manufactured stacks sometimes benefit from integrated cable management.)

Central aperture. Many applications–especially in optics–benefit from transmissive construction of the motion stack. This is difficult or impossible to achieve with a stacked structure of many axes.

Size, weight and fragility. Simply stated, stacks can be substantial in height and mass. And since the bottom stages bear the burden of the entire tall stack, their bearings are vulnerable to brinelling and other damage from inadvertent forces. Besides inviting damage from elbow-knocks when set up, this often necessitates disassembly for shipping, adding cost and hassle and introducing variability when reassembled.

Orthogonality and parasitic errors. Stacked axes interact in complicated ways; for example, runout in the X axis is seen as unwanted motion in the Y and Z axes; angular deviation of an axis similarly imparts motion in the travel-directions of the other axes, with magnitude proportional to the distance to the moving axis. And in stacks, that multiplicative lever-arm can be large.

Prototype of a novel labeling machine designed by PI in cooperation with Tirelli – watch video

Solution: Attack the Stack

It may seem like hyperbole, but all these issues can be avoided by utilizing principles of parallelkinematics. Instead of a tall stack of all the necessary axes with the workpiece perched on top, such systems support a single workpiece in parallel by a tripod or hexapod structure, forming a much stiffer yet lighter-weight structure than is possible by stacking. The best examples of the breed utilize non- or minimally-moving internal cables with conveniently integrated cabling to the controller. User tuning requirements can be eliminated while providing precision and accuracy that can surpass the performance of some of the best available single-axis stages.

Today’s Easy-to-Use Controls

In prior years, the main obstacle to choosing this class of mechanism was the challenge of controlling the workpiece in a user-friendly way, using familiar Cartesian coordinates (X, Y, Z, θX, θY, θZ). This changed with the introduction of PI’s first hexapod two decades ago. That instrument utilized a fully-integrated industrial PC-based digital controller running clever firmware that transparently managed the coordinate transformation process, providing unprecedentedly flexible control in all six degrees of freedom with a programmable rotational center-point, settable by a single software command. A variety of software tools is available now for motion simulation and dynamic patterned motion generation in 6 degrees of freedom, such as used for vehicular simulation and airborne platform simulation and test. Read more: Patterned Motion Generation: Precision in the Time Domain

Simulation tools allow easy calculations of workspace and load limits, when hexapods are used in different orientations, or when loads are cantilevered. Collision avoidance software imports external objects and makes sure that critical positions are excluded by the controller.

One Stop, Many Solutions

These innovations set the tone for PI miCos’ broad array of parallel kinematic mechanisms: innovative solutions that can actually cost less than stacks of six stages of commensurate performance. Today’s offering benefits from years of continuous advancement in mechanical design and controls engineering. Our newest controller integrates an ultra-modern, industrial-class real-time operating system and provides such features and options as TTL motion triggers, analog position-waveform definition, standard internal data recorder with optional analog input, and a high-speed network interface for integration into factory automation systems and remote access. Its sophisticated software support includes comprehensive LabVIEW libraries, MATLAB support, a convenient GUI for setup and test, and well-documented dynamic libraries for Windows, Linux and OS X.

Two Families of Parallel Kinematics

The hexapods utilize a variety of motion technologies for the actuator legs, ranging from brushed or brushless DC servo-motors to high-force PiezoWalk™ non-magnetic actuators. Both fixed- and extendable-strut designs are utilized depending on application needs.

These innovative parallel mechanisms utilize three fixed-length legs in a tripod configuration, driven by three XY actuation modules which provide extended transverse travels for the assembly. Motion technologies can include piezomotors, rotary and linear DC servomotors, and stepper motors. Application story in x-ray diffraction imaging

Hexapod Systems Overview

Many Roles for Stacks

There is nothing wrong with serial kinematics. They work well for many applications and PI offers a large variety of standard and custom designs with stepper motors, piezo motors, and linear motors / air bearings. However, when 4+ degrees of freedom are required, the superior performance of a hexapod or hybrid tripod warrants a close comparison. A PI motion control engineer can help you evaluate advantages and shortcomings of both designs for your application. The benefit of a deeper toolbox and a global team with experience across a multitude of disciplines helps them draw on that experience in consultation with customers, choosing (or custom-developing) optimal solutions and cross-pollinating from related applications in other fields.

A Closer Look at “Impossible” Requests!

Maybe they are impossible… or maybe they just require a fresh approach, or a trick from another application field. Mission-critical PI technology is at the heart of much of today’s cutting edge technology, including semiconductor manufacturing and metrology, photonics packaging and test, genomics, single-molecule biophysics, and ultra-resolution microscopy. Put our experience to work on your problems!

Experience

When we started working on parallel kinematic systems in the late 1980’s and early 1990’s, they were a novelty to many in the field of motion control. The persistent work of our engineers has led to easy to use, highy reliable systems. PI’s first international recognition for hexapod technology dates back to 1995 for the M-800 hexapod system.

1995 Photonics Circle of Excellence Award by Photonics Spectra Magazine for PI’s M-800 commercially available Hexapod 6-axis micropositioning system with controller and software.